• Title/Summary/Keyword: lines of curvature

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A Human Engineering Study on an Original Pattern of Clothing for an Abnormal Type of Figure (이상체형의 의복원형의 인간공학적연구 - 척추만곡체형을 중심으로 -)

  • 박정숙
    • Journal of the Korean Home Economics Association
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    • v.20 no.3
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    • pp.1-8
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    • 1982
  • In this study, we attempted to make an original pattern of clothing for an abnormal type of figure, especially for the type of kyphosis. We measured the curvature of the spine of a woman with kyphosis with a Martin measuring instrument and a silhouetter in the following ways. First, we counted the rate of shrinkage of the standard lines drawn on the surface of the body according as the body moved. Secondly, placing the front and back darts, the front and back shoulder darts and the side darts according to“Munhwa”pattern, we made cubic cuttings of four moving postures as well as the standing one. Thirdly, we superposed the developed patterns of the standing and the moving postures, measuring the position change and the amount to the change of the darts, and compared them. The results are as follows: 1) In the developed pattern of a cubic cutting of the basic pattern and the standing posture, the neckhole became larger than that of the basic pattern, and the waist line was lowered than that of the basic pattern because the center back line was shortened due to the curved backbone.

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Large-scale quasi-steady modelling of a downburst outflow using a slot jet

  • Lin, W.E.;Savory, E.
    • Wind and Structures
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    • v.9 no.6
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    • pp.419-440
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    • 2006
  • This article synthesizes the literature on the meteorology, experimental simulation, and wind engineering ramifications of intense downburst outflows. A novel design of a large-scale test facility and experimental evidence of its validity are presented. A two-dimensional slot jet is used to simulate only the outflow region of a downburst. Profiles of mean velocity and turbulence quantities are acquired using hot-wire anemometry. Comparison with the literature provides empirical evidence that supports the current approach. A geometric analysis considers the validity of applying a two-dimensional approximation for downburst wind loading of structures. This analysis is applicable to power transmission lines in particular. The slot jet concept can be implemented in a large boundary layer wind tunnel to enable large-scale laboratory experiments of thunderstorm wind loads on structures.

미분구적법을 이용한 곡선보의 내평면 진동분석

  • Gang Gi-Jun;Han Ji-Won
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2000.11a
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    • pp.17-26
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    • 2000
  • The early investigators into the in-plane vibration of rings were Hoppe $Hoppe ^{1)}$ and $Love ^{2)}$. $Love ^{2)}$ Improved on Hoppe's theory by allowing for stretching of the ring. $Lamb ^{3)}$ investigated the statics of incomplete ring with various boundary conditions and the dynamics of an incomplete free-free ring of small curvature. Den $Hartog ^{4)}$ used the Rayleigh-Ritz method for finding the lowest natural frequency of circular arcs with simply supported or clamped ends and his work was extended by Volterra and $Morell ^{5)}$ for the vibrations of arches having center lines in the form of cycloids, catenaries or parabolas.(omitted)

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The Insulation Design of Enclosure for Diagnostic Device in Extra High Voltage Line (초고압 선로 진단장치용 외함 절연설계)

  • Kim, Ki-Joon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.3
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    • pp.201-207
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    • 2015
  • In this paper, in order to avoid equipment malfunction due to electromagnetic waves, which can occur when high-voltage live line diagnostic device fabrication, the enclosure structure of the diagnostic device with power lines that can minimize the EMI (electromagnetic interference) was modeled using the FEM (finite element method). Simulation examined the strength of the electric field in the required thickness, material and regions where there is a control board while changing the curvature radius of the corner making the enclosure, and By applying a mechanical design and simulation results that occur during the actual production has been designed for the final design. Most of the simulation results for the electric field is concentrated in the final model, the inner edge of the enclosure could be confirmed that the stable structure.

SYMMETRY ABOUT CIRCLES AND CONSTANT MEAN CURVATURE SURFACE

  • Park, Sung-Ho
    • Korean Journal of Mathematics
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    • v.25 no.4
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    • pp.555-561
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    • 2017
  • We show that a closed curve invariant under inversions with respect to two intersecting circles intersecting at angle of an irrational multiple of $2{\pi}$ is a circle. This generalizes the well known fact that a closed curve symmetric about two lines intersecting at angle of an irrational multiple of $2{\pi}$ is a circle. We use the result to give a different proof of that a compact embedded cmc surface in ${\mathbb{R}}^3$ is a sphere. Finally we show that a closed embedded cmc surface which is invariant under the spherical reflections about two spheres, which intersect at an angle that is an irrational multiple of $2{\pi}$, is a sphere.

Semi-automatic method for surface smoothing

  • Lee, Chong-Sun;Lee, Chong-Won;Park, Se-Hyung
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.249-254
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    • 1987
  • This paper presents a new method for generating smooth free-form surface by local correction. B-spline surface is used for its convenience of local correction, and the direction of surface correction is fixed to the average-surface-normal direction. The surface to be corrected is approximated into a uniform cubic B-spline surface. Then, the smoothness (curvature arrows, iso-parametric lines) of the approximated surface is displayed with B-spline control points. When a control point near the region that needs correction is selected, a new point 1 mm higher than the original control point in the direction of the average surface normal is displayed. And the surface is corrected by giving the amount of control point movement interactively. Since the direction of correction is given by the program and the amount of correction is selected by the user, the method is called semiautomatic. sufficiently smooth surface can be obtained by this method. Examples are given to illustrate the method.

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Transformation of Long Waves with Vertical Acceleration (연식방향의 가속도를 고려한 장파의 변형해석)

  • 여운광
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.2 no.2
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    • pp.112-117
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    • 1990
  • Boussinesq-type equations should be employed in which the water surface profile is considerably steep or the bottom topography is abruptly changed. The primary reason is that the pressure deviates significantly from the hydrostatic pressure distribution due to the large curvature of the stream lines. It is shown that such a Boussinesq type equation can be also derived by making use of the concept of the averaged flow description for specifying the turbulence effects. In addition, a numerical scheme is developed to solve the equations and the effects of the Boussinesq term is briefly investigated.

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Electron Emission Mechanism in the Surface Conduction Electron Emitter Displays

  • Cho, Guang-Sup;Choi, Eun-Ha;Kim, Young-Guon;Kim, Dai-Il
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.139-140
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    • 2000
  • The origin of the display current in the surface conduction electron emitter displays has been verified in the calculation of the electron trajectory. Some electrons move directly toward the display surface as an anode current which is generated due to the inertial force of electron motion along the curved electric field lines with a small curvature near the fissure area..

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Development of Roll Stability Control of Commercial Vehicles with Environment Information (환경 정보를 이용한 상용차량 전복 방지 알고리즘 개발)

  • Park, Dongwoo;Her, Hyundong;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.5 no.1
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    • pp.50-55
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    • 2013
  • When it comes to commercial vehicles, their unique characteristics - center of gravity, size, weight distribution - make them particularly vulnerable to rollover. On top of that, conventional heavy vehicle brake exhibits longer actuation delays caused in part by long air lines from brake pedal to tires. This paper describes rollover prevention algorithm that copes with the characteristics of commercial vehicles. In regard of compensating for high actuating delay, predicted rollover index with short preview time has been designed. Moreover, predicted rollover index with longer preview time has been calculated by using road curvature information based on environment information. When rollover index becomes larger than specific threshold value, desired braking force is calculated in order to decrease the index. At the same time, braking force is distributed to each tire to make yaw rate track desired value.

Geometric Model Decimation Method for Salient Features (돌출된 특징을 위한 기하 모델 단순화 방법)

  • Kim, Soo-Kyun;An, Sung-Og
    • The Journal of Korean Association of Computer Education
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    • v.11 no.4
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    • pp.85-93
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    • 2008
  • This paper proposes a method for generating low-level geometric models with retaining salient features during decimation. Our method employs feature extraction technique for extracting feature lines defined via curvature derivatives on the model (we divide features into ridges and valleys). We add the extraction method to simplification technique (Feature Quadric Error Metric) for making coarse model with features. This paper clearly shows that experimental results have better quality and smaller geometric error than previous methods.

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